This invention relates generally to motorized carts for the transport of paper rolls in a print shop of the type having paper roll unwinders and roll reminders located at the input and output end of a printer. The transport cart of the present invention is particularly designed and configured for the transport of relatively heavy (one thousand pounds and up) paper rolls of the type commonly used with laser printers.
While motorized carts are now available for this purpose, the present invention provides a unique cart that is not only capable of picking up the roll and transporting the roll in a motorized fashion, but wherein the cart is provided at it's aft or rear end with a motorized driven wheel that can be conveniently steered with a hand held yoke having a speed control similar to that provided on a motorcycle. The yoke is manually steerable from the upper, or handle end. The yoke is also moveable fore and aft, such that the cart can be conveniently stopped by a self operating braking system in response to movement of the handle from its active operating position, to a forward or stowed position to set the braking system.
The cart includes a load lifting carriage in the form of a pair of pivotably mounted roll support arms that allow the operator to raise or lower a paper roll from and to position in a roll unwind or rewind machine of the type manufactured by the Assignee of the present application, Energy Saving Products, Inc. of Burlington, Conn., USA.
In the cart of the present invention, the above described yoke includes a lower portion which supports a single motorized drive wheel on a vertical axis (the steering axis) and wherein the drive motor and braking means are provided in the lower portion of the yoke. The drive means comprise an electric motor which is DC driven so as to serve as a brake for the single steerable drive wheel. Rechargable electric batteries are provided on either side of the drive wheel for better balance of the three wheel cart, and to improve traction for the single drive wheel.
The motorized load lifting carriage is operated by a hydraulic system, including at least one hydraulic motor coupled between the carriage and the machine frame. Electric circuitry, including a pump motor for generating hydraulic pressure, is provided in the transport unit, also includes means for controlling both the drive motor and the brake associated with the single steerable rear wheel.